Veritas-bu

[Veritas-bu] Too many small files in filesystem

2005-01-27 17:59:26
Subject: [Veritas-bu] Too many small files in filesystem
From: dale AT daleking DOT org (Dale King)
Date: Fri, 28 Jan 2005 09:59:26 +1100
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On Mon, Jan 24, 2005 at 05:54:54PM -0500, O'Connor, Kyle (Contractor) wrote:
> I have NBU 4.5 running on AIX 5.2.  We have 27 filesystems sized at 200G.
> The files stored within these f/s are on average 120K.  That is, there is
> @1.8 million files within each filesystem.  The backups policy is running
> mpx with 4 streams going to each tape drive ( 8 LTO drives total ).  The
> backups are completing in about 16 hours.  I think the reduction of the
> filesystems to 50G ( < 500K files per f/s ) might help to improve
> performance. Has anyone else experienced this degradation of performance
> with many small files within a f/s, and if so, how did you resolve the
> issue.  Please give specifics for average file size, f/s sizing and
> performance improvements.

What filesystem are you running?  You might find an improvement by using
JFS2 and tuning (per
http://publib16.boulder.ibm.com/pseries/en_US/cmds/aixcmds3/ioo.htm)

Things to look into  are maxclient and maybe inode cache sizes.

You should also look at your disk back end to make sure it is layed out to
support a random access pattern (i.e. you have many small files).

HTH,
Dale

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